Re: Foreign superkey support

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Mon, 07 Aug 2006 12:56:36 GMT
Message-ID: <8MGBg.36195$pu3.473763@ursa-nb00s0.nbnet.nb.ca>

Jon Heggland wrote:
> Are there any DMBSs apart from Dataphor that support foreign superkeys
> without undue hassle? SQL systems support them in that a superkey may be
> declared UNIQUE, and thus referred to by a foreign key, but I'm looking
> for more explicit support.

If it supports constraints based on WFF's, it will. I question whether a need exists for a shortcut.

> Or more generally, are there any DBMSs that support inclusion
> dependencies (apart from the special case of foreign keys, naturally)
> directly?

Any that allow any WFF in a check constraint will.

> Or for that matter, how widespread is multi-relvar constraint support
> (apart from foreign keys)? As far as I know, neither Oracle nor MSSQL
> support SQL ASSERTIONs. Are there any DMBSs that do?

Dunno. Received on Mon Aug 07 2006 - 07:56:36 CDT